Definition:
RSS is a simple data format that is used to retransmit content to subscribers to a website. The format allows you to distribute content without a browser, using software designed to read these RSS feeds (aggregator). Despite this, it is possible to use a browser to view RSS content. The latest versions of major browsers can read RSS feeds without additional software.
Thanks to aggregators or feed readers (programs or sites that allow you to read web sources) can be obtained summaries of all the sites you want from the desktop operating system, e-mail programs or Web applications through operating as aggregators . No need to open a browser and visit dozens of sites.

Web-based aggregators:
Are applications that reside on remote servers that run as applications that run in the website:

Any webmaster can put a section of RSS feeds from different sites have updated their website without having to worry.
It's about putting a piece of code in a web that links to other content, and to share useful information for users.

Implementation:
The most likely already tengais any feed reader installed on your server, then you just need links to feeds.